El Cangrejo, in the Bella Vista corregimiento, is bounded by Vía España and the Transístmica. It grew in the 1950s around a hill, with curving streets that follow the terrain, and today it mixes residential buildings, restaurants, hotels, shops and universities.
That mix shows in the ductwork. A low-rise apartment building with decades of use, a hotel and a ground-floor shop can stand a few steps apart and run very different systems. That is why a visit is planned building by building, making clear who manages each section. The area is about 3 km by road from the Climatiza office, in an approximate calculation.
Data point: In an air system that looked clean to the naked eye, 10⁵ to 10⁶ viable bacteria per cm² were counted on the coil fins (Hugenholtz and Fuerst, 1992). It is a case measured in a single system, not a general figure, which is why the camera looks inside before deciding.